Maxjax lift opinions

But I think I'd have to mount them on a plate,

You would need more than a plate, because you would need front rear as well as side to side tipping forces. My old 2 post is outside. I made an "H" frame out of heavy 2x6 tube, l with added 2" tube triangular braces, which are overkill. They did not need to be that large. The center supports are a PAIR of 2x6 tubes, and even then with the 3/4 or Dakota, the posts "move" in at the top. On the pickups, I use a brace across between the two, hooks to the two carriages
Below, the tubing that will be the center supports
8xs9wg.jpg
Below, half the frame just before erecting. Come-a-long to the radio tower, "gin pole" style
2ds47zq.jpg
Next two below, the upper and lower triangular brace anchors
2ry6jwz.jpg

2wm4e2u.jpg
Below, this is anchor, one on each side on the carriages for a cross brace on the pickups. Keeps posts from "creeping" inwards
34gwrqe.jpg
Last two, "in the air" and a view of the base. Identical "U" to make the "H" comes out forwared
174spv.jpg

ejzsiu.jpg

THIS IS THE BEST MONEY I EVER SPENT!!! Regardless of not having a shop